Testing Pentax 645 35mm - SMC Pentax-A vs HD Pentax-D FA

**RICHARD L.** · 09-22-2020, 08:06 AM - **1 Like**

No, I never put it on my 645N but the results obtained with the 645Z are delightful and above any reproach. As someone I knew said : "Better than the bottom of a Coke bottle, eh!"

Regards

Last edited by RICHARD L.; 09-22-2020 at 08:11 AM.

**barondla** · 09-22-2020, 08:44 PM

Originally posted by Pål Jensen

Have you tried it on a full frame 645?

Corners are OK if stopped down. The images below are shot with a 645NII

Beautiful images. Can't knock any lens that records at this level. The 33-55 performs well on 645 digital crop and, with more care, on full size film.

Thanks for sharing,
barondla

diggles · 09-23-2020, 04:43 AM - **1 Like**

Originally posted by rdeloe

Thanks for saving me the time and money.

Cheers to that!

**RICHARD L.** · 10-08-2020, 02:20 PM - **1 Like**

Lake Simon in the fall, on tripod and f/9.

169 · 04-15-2023, 10:30 AM

I feel this thread should become the definitive statement on Pentax 645 wide angles, but there's still a great deal of contradictory intel.
About 15 years ago, I wrote a review of 35mm shift lenses for 35mm DSLRs and I promised to compare them with the Pentax 645 FA 35mm that I was impressed with via a Zörk PSA. I haven't got round to it yet, but I'm working on it.
At the time, the A-SMC was generally considered the poor relation of the FA. Contrary to what was stated at the top of this thread, and elsewhere in reviews, it's a revised optical formula: the old lens is 9/8; the FA and D-FA are 10/7.
Some are now saying the SMC is sharper than the FA in the outer image circle; some the opposite. Everyone seems to agree that the D-FA is a step up from both all round, but we're seeing pushback against the current valuation: certainly the SMC is great value – and still a great lens – but I don't feel confident about the reputation of the SMC v FA. And now, the long maligned 33-55mm is getting some love.
How the 67 lenses compare optically also seems uncertain: here on the forum, you can read than the 67 45/4 is both much better and much worse than the 645 45-85mm.
Would anyone in the UK like to collaborate on a little series of tests that compare them on a level playing field to some 35mm shift lenses?

rdeloe · 04-15-2023, 07:40 PM

Originally posted by 169

I feel this thread should become the definitive statement on Pentax 645 wide angles, but there's still a great deal of contradictory intel.
About 15 years ago, I wrote a review of 35mm shift lenses for 35mm DSLRs and I promised to compare them with the Pentax 645 FA 35mm that I was impressed with via a Zörk PSA. I haven't got round to it yet, but I'm working on it.
At the time, the A-SMC was generally considered the poor relation of the FA. Contrary to what was stated at the top of this thread, and elsewhere in reviews, it's a revised optical formula: the old lens is 9/8; the FA and D-FA are 10/7.
Some are now saying the SMC is sharper than the FA in the outer image circle; some the opposite. Everyone seems to agree that the D-FA is a step up from both all round, but we're seeing pushback against the current valuation: certainly the SMC is great value – and still a great lens – but I don't feel confident about the reputation of the SMC v FA. And now, the long maligned 33-55mm is getting some love.
How the 67 lenses compare optically also seems uncertain: here on the forum, you can read than the 67 45/4 is both much better and much worse than the 645 45-85mm.
Would anyone in the UK like to collaborate on a little series of tests that compare them on a level playing field to some 35mm shift lenses?

I'm not in the UK so can't help you with this project. However, I have the SMC Pentax-A 645 35/3.5 and the HD Pentax-D FA 645 35/3.5, and I've had the FA 645 35/3.5. I also have the 645 45-85 (A) and have had the Pentax 67 45/4. I've only used them on a GFX 50R as tilt-shift lenses if that's relevant.

Anyway, long story short, let me know if you want to buy my HD Pentax-D FA 645 35/3.5.

It's not better than my A as a shift lens in any way that I can measure or replicate. It's not sharper, and it's not better at the edges. The one thing it has going for it is Lightroom has a built-in correction profile (but that profile does a good job on the A too so it's not much of an advantage). The P67 45 is a very nice lens, but it's soft on my 50R once I zoom in. The 45mm end of the 45-85 leaves it for dead on my GFX 50R. I'm not saying you can't make excellent photographs with the P67 45. I know people who do. But if you need sharpness and detail, it comes up short.

**Focusrite** · 04-15-2023, 08:36 PM

Hearing this is a bit of a shame, I was pondering about whether the D-FA would be an upgrade over the A for shifting. One question that I have is in regard to the image circle size. Someone earlier in the thread mentioned that the files of view of the A version is slightly wider (by how much, I don't recall being mentioned), and I'm curious as to whether you think the image circle of the D-FA is any greater to compensate?

I use my copy of the A version with some success on a GFX50R and the Fotodiox T/S adapter, and at the extremes of shift (12mm, I think) the image begins to degrade markedly and the corners darken. Mounting a filter makes the vignetting worse, and perhaps that is an advantage to the D-FA for having a larger filter thread?

rdeloe · 04-16-2023, 06:57 PM - **1 Like**

The D-FA has a slightly narrower angle of view than the A. If the A is 35mm, the D-FA is 36mm (roughly).

To check the size of the image circle, I just put them both on my Arca-Swiss F-Universalis, which can shift to 25mm. There's no difference in the size of the image circle.

169 · 04-17-2023, 03:50 AM

Originally posted by rdeloe

I'm not in the UK so can't help you with this project. However, I have the SMC Pentax-A 645 35/3.5 and the HD Pentax-D FA 645 35/3.5, and I've had the FA 645 35/3.5. I also have the 645 45-85 (A) and have had the Pentax 67 45/4. I've only used them on a GFX 50R as tilt-shift lenses if that's relevant.

Anyway, long story short, let me know if you want to buy my HD Pentax-D FA 645 35/3.5.

It's not better than my A as a shift lens in any way that I can measure or replicate. It's not sharper, and it's not better at the edges. The one thing it has going for it is Lightroom has a built-in correction profile (but that profile does a good job on the A too so it's not much of an advantage). The P67 45 is a very nice lens, but it's soft on my 50R once I zoom in. The 45mm end of the 45-85 leaves it for dead on my GFX 50R. I'm not saying you can't make excellent photographs with the P67 45. I know people who do. But if you need sharpness and detail, it comes up short.

You're in a great position to comment - thanks for your input. It's the long story I'm interested in – don't cut it short on our account please!

In my experience, every P645 and 67 optic passes the test of being able to make great pictures with. They're safely among the best MF lenses that aren't Hasseblad. But the 33-55, SMC 35, FA35, D-FA35 differ by design, will have different merits, and are directly comparable. Similarly, the 45-55mm lenses.

This isn't necessarily my experience, but collating received opinion and weighting against outlying data points (ie, from an AI perspective), would folks agree this is the generally-held view of these lenses in 2023, now largely based on their performance on 35mm and GFX? We might expect a shift of opinion since their original reputation was made using different cameras.

35mm

SMC-A: better in outer image circle than FA35; worse flare, similar geometric distortion, similar CA
FA35: slightly sharper in centre circle than SMC-A, especially at wider apertures; worse field curvature
D-FA: better coatings than either (reduced flare), but otherwise similar to FA
33-55mm: peak performance at 33-35mm, but greater distortion. Comparable centre-frame resolution to 35mm primes at f11-16 but weaker outer image circle

45-55mm

67 55/4 (v3): best optically centre frame; excellent bokeh
55/4 (earlier versions): uncertain how they compare with 45mm variants
645 55/2.8: not sharper overall than 645 45-85: some say yes; others no: likely better at wide apertures; perhaps not as good framewide at f8-f11. Busy bokeh.
645 45-85: best optically in outer image circle at 45-55mm (deteriorates with increased focal length); good bokeh, slightly worse distortion
645 45/2.8: uncertain how compares with 67 45/4 (worse than SMC 35/3.5)
67 45/4: uncertain how compares with 645 45/2.8, but larger image circle likely produces better 'corners'. Flare-prone.

Please feel free to revise or contradict this summary . . .

rdeloe · 04-17-2023, 06:28 AM - **2 Likes**

I think your summary list is reasonable. I'd offer a few friendly amendments that can be taken with the usual grain of salt:

I haven't noticed flare as an issue on the SMC Pentax-A 645 35/3.5. I use it without a lens hood. To protect against stray light, I'll use whatever I can put in the way (usually my hat). It's one of the three lenses I use the most, so I'm confident that flare isn't a major issue. I can't comment on whether the later ones have better flare resistance.

A friend of mine, who isn't around to comment anymore, had the 33-55mm and use it as a shift lens on a GFX 100S outfit. He was extremely picky, but very impressed, especially given the negative reputation.

The 645 55/2.8 is an interesting one. I used it as a shift lens on a Sony A7R setup and thought it was fine. However, when I tried it on my GFX 50R outfit as a shift lens (two separate times), it wasn't. Centre performance unshifted was fine, but it fell apart at the edges until f/11 unshifted. I concluded at the time that it had significant field curvature because I could get better edges and corners if I focused on the edges.

The 67 55/4 third generation is a star. It's very sharp across the frame and has the big image circle I needed. I didn't keep it because it's large and heavy for my setup, and there are lighter options. Someone setting up a tilt-shift outfit who needed this focal length and didn't want to get into modifying lenses could be very happy with this one.

Everyone seems to say that the 45-85 is not good at the long end. I never saw that, and I explored that very thoroughly. I would use it without hesitation at any focal length. It has quite strong barrel distortion throughout the whole zoom range (stronger at 45 and weaker at 85). I'd have to check but I suspect there might be a moustache form in the whole image circle. For best performance across the frame you definitely want to close down to f/8, but it's absolutely usable wide open across the whole zoom range. I would describe this lens as ridiculously good given the price. It's without a doubt the best 45mm Pentax medium format lens (it's not even close). As a bonus, the image circle of the A is massive in the middle of the zoom range. The optics of the FA are supposed to be the same, but I've never used one so I'm not sure if the image circle is also massive on the FA. It's a property of some zoom lens designs (image circle increases in the mid-range), but the lens designers may have "choked" it -- like they did for the FA 150-300.

The reasons my A 45-85 stays in the drawer are it's too big to use comfortably on my technical cameras; the rotating front element is a pain with CPLs; and it's troublesome to use with tilt and swing. Having said that, if this was the only lens I had with me, I could do almost everything I need to do with it.

The 67 45mm is a real shame. It's small and light (relatively speaking), has nice colours, a big image circle, and moderate barrel distortion. It's only flaw for my purposes is it doesn't quite have the resolving power I wanted. I can see why people thought it was great on film. On digital, if you need the big image circle more than you need maximum possible resolving power, it's a good option. Some attention to sharpness in post does help. Unfortunately, I didn't use it enough to be able to comment on flare.

I came close to buying a 645 45/2.8 on more than one occasion, just to see if all the bad press was warranted. However, enough people whose opinion I respect said it was worse than the 55/2.8, and that one didn't cut it for me so I never bothered. It's a shame because it's a focal length I really like. Unless someone lends me one I'll never try this one because I have a superb Mamiya N 43mm f/4.5 L that I use now.

As a general observation about the whole lineup, I really like Pentax medium format because they're solid, no-fuss professional lenses. If my A 35/3.5 had to be replaced, I'm confident I could buy any one of the many available for sale that looked to be in decent condition and it would be fine; I wouldn't have to worry about copy variation. I think of them as the Honda of lenses: high quality, reliable tools. On my setup I'm only using one Pentax now (the irreplaceable A 645 35/3.5). The other lenses are Mamiya G and N, and Schneider-Kreuznach. But there's no question I could do what i need to do with Pentax medium format lenses.

**RICHARD L.** · 04-17-2023, 06:53 AM

Hello !

I think you forgot the new 645 DFA 55 mm f/2.8. It has no aperture opening ring and may be unwieldy to use on other than a Pentax 645Z but it performs like no other lens, except the P67 55 mm f/4 (which is a PERFECT lens).

Regards

Sorry for the HUGE lettering as my vision begins to be cloudy with cataracts ...

---------- Post added 04-17-23 at 10:03 AM ----------

I was forgetting ... last year, i found a like-new 645 FA 35 mm f/3.5 for 480 $ on eBay-Japan. It performs excellently on my Pentax 645Z and I never saw any issue with spherical aberrations. It is true I never use it at less than f/6.3 but the photogram seems uniformly sharp on a small 33 X 44 digital sensor; maybe it was a different story on a film 645 camera.

I find this post very interesting and I will follow it intently.

Regards

645 FA 35 mm @ f/6.3

645 FA 35 mm @ f/11

169 · 04-17-2023, 02:24 PM - **2 Likes**

Originally posted by rdeloe

The 67 55/4 third generation is a star. It's very sharp across the frame and has the big image circle I needed. I didn't keep it because it's large and heavy for my setup, and there are lighter options. Someone setting up a tilt-shift outfit who needed this focal length and didn't want to get into modifying lenses could be very happy with this one.

The reasons my A 45-85 stays in the drawer are it's too big to use comfortably on my technical cameras; the rotating front element is a pain with CPLs; and it's troublesome to use with tilt and swing. Having said that, if this was the only lens I had with me, I could do almost everything I need to do with it.

Curious about lighter options that match the performance of the 55/4 . . .
Weight is the deal-breaker for the 45-85mm for me, too: the tilt/shift adaptors for 35mm cameras don't feel up to the job of wrangling a front-heavy 870g.

I now have on order the 33-55 and FA35, and should have the SMC 35/3.5 and 55/2.8 within a week. I'll report back when I've been able to compare them to my Olympus 35 shift on the Panasonic S1R.

As an aside, I'm also interested in how they compare to the Zenzanon 40PE and 45/4 for RF645. Rob also drew my attention to the Contax 645 35/3.5, which seems to be a refinement of the PC-Distagon 35/2.8. Will the SMC still stand tall in this company? People seem to believe so.

**Ed Hurst** · 04-18-2023, 07:37 PM

Has anyone tried shifting the 25mm DFA (not the DA) at all? How much movement can be achieved?

**kaseki** · 04-19-2023, 10:33 AM

Originally posted by Ed Hurst

Has anyone tried shifting the 25mm DFA (not the DA) at all? How much movement can be achieved?

Optically, transverse motion equal to half the difference between film size and focal plane array size should be possible. However, the last element is located on the focal plane side of the lens mount. Mechanical difference between infinity focus and past infinity focus is slight. I would think significant modification (read ravaging) of the lens assembly rear parts would be needed to adapt it to a traversing mechanism and keep the optics at the correct distance from the focal plane.

**Focusrite** · 04-19-2023, 02:40 PM

Originally posted by Ed Hurst

Has anyone tried shifting the 25mm DFA (not the DA) at all? How much movement can be achieved?

A forum user going by Gerd made some comments a number of years ago about using the 25mm on a Cambo Actus and GFX ( small tech-cam rig, as you probably know ). He seemed to be content with the results, but also made comments elsewhere that the overall performance fell short of the GF 23mm in comparison ( unshifted ). His comments were brief, and I private messaged him a few months ago to ask for some more indepth info about how it performs when shifted. He never responded, and hasn't been active on the forum for some time now. I might try to dig up the thread later when I have some time.

A shame, as I also am highly curious about how well it would shift, and there is precious little on the 'net about it. His experience would be invaluable.

10-08-2020, 02:20 PM - 1 Like	#49
RICHARD L. Loyal Site Supporter Join Date: Oct 2018 Location: Quebec City, Quebec Posts: 6,575	The 645 A 35 mm f/3.5 is a swell lens in its own right. Lake Simon in the fall, on tripod and f/9.

04-17-2023, 06:53 AM	#56
RICHARD L. Loyal Site Supporter Join Date: Oct 2018 Location: Quebec City, Quebec Posts: 6,575	Hello ! I think you forgot the new 645 DFA 55 mm f/2.8. It has no aperture opening ring and may be unwieldy to use on other than a Pentax 645Z but it performs like no other lens, except the P67 55 mm f/4 (which is a PERFECT lens). Regards Sorry for the HUGE lettering as my vision begins to be cloudy with cataracts ... ---------- Post added 04-17-23 at 10:03 AM ---------- I was forgetting ... last year, i found a like-new 645 FA 35 mm f/3.5 for 480 $ on eBay-Japan. It performs excellently on my Pentax 645Z and I never saw any issue with spherical aberrations. It is true I never use it at less than f/6.3 but the photogram seems uniformly sharp on a small 33 X 44 digital sensor; maybe it was a different story on a film 645 camera. I find this post very interesting and I will follow it intently. Regards 645 FA 35 mm @ f/6.3 645 FA 35 mm @ f/11 Last edited by RICHARD L.; 04-17-2023 at 07:05 AM.

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09-22-2020, 08:06 AM - 1 Like	#46
RICHARD L. Loyal Site Supporter Join Date: Oct 2018 Location: Quebec City, Quebec Posts: 6,575	No, I never put it on my 645N but the results obtained with the 645Z are delightful and above any reproach. As someone I knew said : "Better than the bottom of a Coke bottle, eh!" Regards Last edited by RICHARD L.; 09-22-2020 at 08:11 AM.

09-22-2020, 08:44 PM	#47
barondla Site Supporter Join Date: Sep 2006 Location: midwest, United States Photos: Gallery \| Albums Posts: 5,714	Originally posted by Pål Jensen Have you tried it on a full frame 645? Corners are OK if stopped down. The images below are shot with a 645NII Beautiful images. Can't knock any lens that records at this level. The 33-55 performs well on 645 digital crop and, with more care, on full size film. Thanks for sharing, barondla

09-23-2020, 04:43 AM - 1 Like	#48
diggles New Member Join Date: Jun 2020 Location: Windsor, Colorado Posts: 19 Original Poster	Originally posted by rdeloe Thanks for saving me the time and money. Cheers to that!

04-15-2023, 10:30 AM	#50
169 Junior Member Join Date: Feb 2022 Posts: 38	I feel this thread should become the definitive statement on Pentax 645 wide angles, but there's still a great deal of contradictory intel. About 15 years ago, I wrote a review of 35mm shift lenses for 35mm DSLRs and I promised to compare them with the Pentax 645 FA 35mm that I was impressed with via a Zörk PSA. I haven't got round to it yet, but I'm working on it. At the time, the A-SMC was generally considered the poor relation of the FA. Contrary to what was stated at the top of this thread, and elsewhere in reviews, it's a revised optical formula: the old lens is 9/8; the FA and D-FA are 10/7. Some are now saying the SMC is sharper than the FA in the outer image circle; some the opposite. Everyone seems to agree that the D-FA is a step up from both all round, but we're seeing pushback against the current valuation: certainly the SMC is great value – and still a great lens – but I don't feel confident about the reputation of the SMC v FA. And now, the long maligned 33-55mm is getting some love. How the 67 lenses compare optically also seems uncertain: here on the forum, you can read than the 67 45/4 is both much better and much worse than the 645 45-85mm. Would anyone in the UK like to collaborate on a little series of tests that compare them on a level playing field to some 35mm shift lenses?

04-15-2023, 07:40 PM	#51
rdeloe Forum Member Join Date: Aug 2015 Posts: 62	Originally posted by 169 I feel this thread should become the definitive statement on Pentax 645 wide angles, but there's still a great deal of contradictory intel. About 15 years ago, I wrote a review of 35mm shift lenses for 35mm DSLRs and I promised to compare them with the Pentax 645 FA 35mm that I was impressed with via a Zörk PSA. I haven't got round to it yet, but I'm working on it. At the time, the A-SMC was generally considered the poor relation of the FA. Contrary to what was stated at the top of this thread, and elsewhere in reviews, it's a revised optical formula: the old lens is 9/8; the FA and D-FA are 10/7. Some are now saying the SMC is sharper than the FA in the outer image circle; some the opposite. Everyone seems to agree that the D-FA is a step up from both all round, but we're seeing pushback against the current valuation: certainly the SMC is great value – and still a great lens – but I don't feel confident about the reputation of the SMC v FA. And now, the long maligned 33-55mm is getting some love. How the 67 lenses compare optically also seems uncertain: here on the forum, you can read than the 67 45/4 is both much better and much worse than the 645 45-85mm. Would anyone in the UK like to collaborate on a little series of tests that compare them on a level playing field to some 35mm shift lenses? I'm not in the UK so can't help you with this project. However, I have the SMC Pentax-A 645 35/3.5 and the HD Pentax-D FA 645 35/3.5, and I've had the FA 645 35/3.5. I also have the 645 45-85 (A) and have had the Pentax 67 45/4. I've only used them on a GFX 50R as tilt-shift lenses if that's relevant. Anyway, long story short, let me know if you want to buy my HD Pentax-D FA 645 35/3.5. It's not better than my A as a shift lens in any way that I can measure or replicate. It's not sharper, and it's not better at the edges. The one thing it has going for it is Lightroom has a built-in correction profile (but that profile does a good job on the A too so it's not much of an advantage). The P67 45 is a very nice lens, but it's soft on my 50R once I zoom in. The 45mm end of the 45-85 leaves it for dead on my GFX 50R. I'm not saying you can't make excellent photographs with the P67 45. I know people who do. But if you need sharpness and detail, it comes up short.

04-15-2023, 08:36 PM	#52
Focusrite Loyal Site Supporter Join Date: Jun 2014 Photos: Gallery Posts: 206	Hearing this is a bit of a shame, I was pondering about whether the D-FA would be an upgrade over the A for shifting. One question that I have is in regard to the image circle size. Someone earlier in the thread mentioned that the files of view of the A version is slightly wider (by how much, I don't recall being mentioned), and I'm curious as to whether you think the image circle of the D-FA is any greater to compensate? I use my copy of the A version with some success on a GFX50R and the Fotodiox T/S adapter, and at the extremes of shift (12mm, I think) the image begins to degrade markedly and the corners darken. Mounting a filter makes the vignetting worse, and perhaps that is an advantage to the D-FA for having a larger filter thread?

04-16-2023, 06:57 PM - 1 Like	#53
rdeloe Forum Member Join Date: Aug 2015 Posts: 62	The D-FA has a slightly narrower angle of view than the A. If the A is 35mm, the D-FA is 36mm (roughly). To check the size of the image circle, I just put them both on my Arca-Swiss F-Universalis, which can shift to 25mm. There's no difference in the size of the image circle.

04-17-2023, 03:50 AM	#54
169 Junior Member Join Date: Feb 2022 Posts: 38	Originally posted by rdeloe I'm not in the UK so can't help you with this project. However, I have the SMC Pentax-A 645 35/3.5 and the HD Pentax-D FA 645 35/3.5, and I've had the FA 645 35/3.5. I also have the 645 45-85 (A) and have had the Pentax 67 45/4. I've only used them on a GFX 50R as tilt-shift lenses if that's relevant. Anyway, long story short, let me know if you want to buy my HD Pentax-D FA 645 35/3.5. It's not better than my A as a shift lens in any way that I can measure or replicate. It's not sharper, and it's not better at the edges. The one thing it has going for it is Lightroom has a built-in correction profile (but that profile does a good job on the A too so it's not much of an advantage). The P67 45 is a very nice lens, but it's soft on my 50R once I zoom in. The 45mm end of the 45-85 leaves it for dead on my GFX 50R. I'm not saying you can't make excellent photographs with the P67 45. I know people who do. But if you need sharpness and detail, it comes up short. You're in a great position to comment - thanks for your input. It's the long story I'm interested in – don't cut it short on our account please! In my experience, every P645 and 67 optic passes the test of being able to make great pictures with. They're safely among the best MF lenses that aren't Hasseblad. But the 33-55, SMC 35, FA35, D-FA35 differ by design, will have different merits, and are directly comparable. Similarly, the 45-55mm lenses. This isn't necessarily my experience, but collating received opinion and weighting against outlying data points (ie, from an AI perspective), would folks agree this is the generally-held view of these lenses in 2023, now largely based on their performance on 35mm and GFX? We might expect a shift of opinion since their original reputation was made using different cameras. 35mm SMC-A: better in outer image circle than FA35; worse flare, similar geometric distortion, similar CA FA35: slightly sharper in centre circle than SMC-A, especially at wider apertures; worse field curvature D-FA: better coatings than either (reduced flare), but otherwise similar to FA 33-55mm: peak performance at 33-35mm, but greater distortion. Comparable centre-frame resolution to 35mm primes at f11-16 but weaker outer image circle 45-55mm 67 55/4 (v3): best optically centre frame; excellent bokeh 55/4 (earlier versions): uncertain how they compare with 45mm variants 645 55/2.8: not sharper overall than 645 45-85: some say yes; others no: likely better at wide apertures; perhaps not as good framewide at f8-f11. Busy bokeh. 645 45-85: best optically in outer image circle at 45-55mm (deteriorates with increased focal length); good bokeh, slightly worse distortion 645 45/2.8: uncertain how compares with 67 45/4 (worse than SMC 35/3.5) 67 45/4: uncertain how compares with 645 45/2.8, but larger image circle likely produces better 'corners'. Flare-prone. Please feel free to revise or contradict this summary . . .

04-17-2023, 06:28 AM - 2 Likes	#55
rdeloe Forum Member Join Date: Aug 2015 Posts: 62	I think your summary list is reasonable. I'd offer a few friendly amendments that can be taken with the usual grain of salt: I haven't noticed flare as an issue on the SMC Pentax-A 645 35/3.5. I use it without a lens hood. To protect against stray light, I'll use whatever I can put in the way (usually my hat). It's one of the three lenses I use the most, so I'm confident that flare isn't a major issue. I can't comment on whether the later ones have better flare resistance. A friend of mine, who isn't around to comment anymore, had the 33-55mm and use it as a shift lens on a GFX 100S outfit. He was extremely picky, but very impressed, especially given the negative reputation. The 645 55/2.8 is an interesting one. I used it as a shift lens on a Sony A7R setup and thought it was fine. However, when I tried it on my GFX 50R outfit as a shift lens (two separate times), it wasn't. Centre performance unshifted was fine, but it fell apart at the edges until f/11 unshifted. I concluded at the time that it had significant field curvature because I could get better edges and corners if I focused on the edges. The 67 55/4 third generation is a star. It's very sharp across the frame and has the big image circle I needed. I didn't keep it because it's large and heavy for my setup, and there are lighter options. Someone setting up a tilt-shift outfit who needed this focal length and didn't want to get into modifying lenses could be very happy with this one. Everyone seems to say that the 45-85 is not good at the long end. I never saw that, and I explored that very thoroughly. I would use it without hesitation at any focal length. It has quite strong barrel distortion throughout the whole zoom range (stronger at 45 and weaker at 85). I'd have to check but I suspect there might be a moustache form in the whole image circle. For best performance across the frame you definitely want to close down to f/8, but it's absolutely usable wide open across the whole zoom range. I would describe this lens as ridiculously good given the price. It's without a doubt the best 45mm Pentax medium format lens (it's not even close). As a bonus, the image circle of the A is massive in the middle of the zoom range. The optics of the FA are supposed to be the same, but I've never used one so I'm not sure if the image circle is also massive on the FA. It's a property of some zoom lens designs (image circle increases in the mid-range), but the lens designers may have "choked" it -- like they did for the FA 150-300. The reasons my A 45-85 stays in the drawer are it's too big to use comfortably on my technical cameras; the rotating front element is a pain with CPLs; and it's troublesome to use with tilt and swing. Having said that, if this was the only lens I had with me, I could do almost everything I need to do with it. The 67 45mm is a real shame. It's small and light (relatively speaking), has nice colours, a big image circle, and moderate barrel distortion. It's only flaw for my purposes is it doesn't quite have the resolving power I wanted. I can see why people thought it was great on film. On digital, if you need the big image circle more than you need maximum possible resolving power, it's a good option. Some attention to sharpness in post does help. Unfortunately, I didn't use it enough to be able to comment on flare. I came close to buying a 645 45/2.8 on more than one occasion, just to see if all the bad press was warranted. However, enough people whose opinion I respect said it was worse than the 55/2.8, and that one didn't cut it for me so I never bothered. It's a shame because it's a focal length I really like. Unless someone lends me one I'll never try this one because I have a superb Mamiya N 43mm f/4.5 L that I use now. As a general observation about the whole lineup, I really like Pentax medium format because they're solid, no-fuss professional lenses. If my A 35/3.5 had to be replaced, I'm confident I could buy any one of the many available for sale that looked to be in decent condition and it would be fine; I wouldn't have to worry about copy variation. I think of them as the Honda of lenses: high quality, reliable tools. On my setup I'm only using one Pentax now (the irreplaceable A 645 35/3.5). The other lenses are Mamiya G and N, and Schneider-Kreuznach. But there's no question I could do what i need to do with Pentax medium format lenses.

04-17-2023, 02:24 PM - 2 Likes	#57
169 Junior Member Join Date: Feb 2022 Posts: 38	Originally posted by rdeloe The 67 55/4 third generation is a star. It's very sharp across the frame and has the big image circle I needed. I didn't keep it because it's large and heavy for my setup, and there are lighter options. Someone setting up a tilt-shift outfit who needed this focal length and didn't want to get into modifying lenses could be very happy with this one. The reasons my A 45-85 stays in the drawer are it's too big to use comfortably on my technical cameras; the rotating front element is a pain with CPLs; and it's troublesome to use with tilt and swing. Having said that, if this was the only lens I had with me, I could do almost everything I need to do with it. Curious about lighter options that match the performance of the 55/4 . . . Weight is the deal-breaker for the 45-85mm for me, too: the tilt/shift adaptors for 35mm cameras don't feel up to the job of wrangling a front-heavy 870g. I now have on order the 33-55 and FA35, and should have the SMC 35/3.5 and 55/2.8 within a week. I'll report back when I've been able to compare them to my Olympus 35 shift on the Panasonic S1R. As an aside, I'm also interested in how they compare to the Zenzanon 40PE and 45/4 for RF645. Rob also drew my attention to the Contax 645 35/3.5, which seems to be a refinement of the PC-Distagon 35/2.8. Will the SMC still stand tall in this company? People seem to believe so.

04-18-2023, 07:37 PM	#58
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	Has anyone tried shifting the 25mm DFA (not the DA) at all? How much movement can be achieved?

04-19-2023, 10:33 AM	#59
kaseki Loyal Site Supporter Join Date: Dec 2017 Photos: Gallery \| Albums Posts: 1,138	Originally posted by Ed Hurst Has anyone tried shifting the 25mm DFA (not the DA) at all? How much movement can be achieved? Optically, transverse motion equal to half the difference between film size and focal plane array size should be possible. However, the last element is located on the focal plane side of the lens mount. Mechanical difference between infinity focus and past infinity focus is slight. I would think significant modification (read ravaging) of the lens assembly rear parts would be needed to adapt it to a traversing mechanism and keep the optics at the correct distance from the focal plane.

04-19-2023, 02:40 PM	#60
Focusrite Loyal Site Supporter Join Date: Jun 2014 Photos: Gallery Posts: 206	Originally posted by Ed Hurst Has anyone tried shifting the 25mm DFA (not the DA) at all? How much movement can be achieved? A forum user going by Gerd made some comments a number of years ago about using the 25mm on a Cambo Actus and GFX ( small tech-cam rig, as you probably know ). He seemed to be content with the results, but also made comments elsewhere that the overall performance fell short of the GF 23mm in comparison ( unshifted ). His comments were brief, and I private messaged him a few months ago to ask for some more indepth info about how it performs when shifted. He never responded, and hasn't been active on the forum for some time now. I might try to dig up the thread later when I have some time. A shame, as I also am highly curious about how well it would shift, and there is precious little on the 'net about it. His experience would be invaluable.